Add comment field to entity_type entity_test

Closes #3474680

core/modules/comment/tests/src/Functional/CommentNonNodeTest.php

@@ -440,6 +440,7 @@ public function testCommentFunctionality(): void {
       'target_entity_type_id' => 'entity_test',
     ]);
     $bundle->save();
+    $this->addDefaultCommentField('entity_test', 'entity_test', 'foobar');
 
     // Add a new comment field.
     $storage_edit = [